This disclosure generally relates to a changeover switch and in particular, relates to a high-voltage automatic changeover switch for use in a dual-energy or multi-energy electron accelerator system.
An electron accelerator is a device for accelerating charged particles to have a high energy by an electromagnetic field in vacuum, while an electron linear accelerator is a device for accelerating electrons along a linear track by a microwave electromagnetic field. The electron accelerator is widely used in the fields of industry non-destructive test, custom container inspection, high-energy CT, electron beam radiation and so on. In order to obtain a high-intensity acceleration electric field, the electron linear accelerator for accelerating electrons by the microwave electromagnetic field generates a large instantaneous microwave power and works in a pulse form. A high-voltage pulse modulator is a main composite part of such a microwave source and mainly includes a magnetron or klystron, a high-voltage module, a charging module, a pulse forming network module, and a pulse transformer, etc. The high-voltage pulse generated by the high-voltage pulse modulator is supplied to the magnetron and an electron gun, and the high voltage is usually 48 KV and 20 KV or so.
A dual-energy or multi-energy electron accelerator system is an electron accelerator system capable of outputting electron beam streams with two or more kinds of energies. Compared with the traditional single-energy electron accelerator system, the dual-energy or multi-energy electron accelerator system is different not only in diversity of stand-alone energies but having a greater technical advantage of its combination with a new-generation detector system, data image processing system and so on to distinguish different substance materials. In the traditional fields of industry non-destructive test, custom container inspection, high-energy CT, and so on, the single-energy accelerator system can only be used to identify shapes of the object, whereas the dual-energy or multi-energy accelerator system can be used to identify both shapes and material of the object. Thus, the dual-energy or multi-energy accelerator system has wider prospects for application.
In order to obtain electron beam streams with different energies in an accelerator system, it is necessary to realize it by supplying different operating voltages to the magnetron and electron gun. The selection of different operating voltages to the magnetron and electron gun is realized by a high-voltage automatic changeover switch. This high-voltage automatic changeover switch is required to have a high voltage-resistant performance, not less than 50 KV, to allow a great pulse current to pass through, not lower than 500 A, to have a good contact performance and a high stability, and to be automatically switchable. The high-voltage automatic changeover switch which sufficiently satisfies such application conditions has not been found in the existing high-voltage components and devices.